The present invention relates to an electrical circuit board and a method for making a multi-layer electrical circuit board and, more particularly, to a method for making a multi-layer electrical circuit board having at least one electrically conductive interconnection portion or xe2x80x9cviaxe2x80x9d which selectively allows various portions and/or components residing within and/or upon the multi-layer electrical circuit board to be electrically and operatively connected, and which further includes at least one air-bridge or crossover member to desirably increase component density.
Multi-layer circuit boards allow electrical components to selectively and operatively populate opposed surfaces of each board (or other respective interior portions of each of the boards), thereby desirably allowing each of the electrical circuit boards to contain a relatively large amount of electrical components which efficiently and densely populate the respective boards. It is desirable to allow at least some of the component-containing surfaces or portions of a created and/or formed electrical circuit board to communicate and/or to be selectively interconnected, thereby allowing the contained electrical components to cooperatively and selectively form one or more desired electrical circuits. This desired communication and/or interconnection typically requires the use of shared electrical ground planes, the transmittal of electrical power and/or control type signals between each of the component containing surfaces or board portions, and/or the connection of components which respectively reside on opposed surfaces and/or within diverse portions of the formed electrical circuit board.
This desired interconnection typically requires that one or more holes be drilled within and/or through each of the circuit boards, thereby creating at least one xe2x80x9cthrough holexe2x80x9d or xe2x80x9cviaxe2x80x9d traversing each of the opposed component containing surfaces and through the various interior circuit board portions. Such drilling is undesirable since it is relatively time consuming, costly, potentially causes damage to significant numbers of the formed electrical circuit boards requiring these circuit boards to be destroyed, and requires costly and inefficient electroless and/or electrolytic plating of the formed holes or xe2x80x9cviasxe2x80x9d.
While some attempts have been made to obviate the need for such plating, such as by the use of a conductive epoxy within each of the drilled holes, these attempts have not produced reliable electrical interconnections and these produced interconnections are not typically adapted to allow the communication of electrical power signals between the board surfaces. The produced apertures also do not securely and reliably receive a component.
Further, it is desirable to form xe2x80x9cair-bridgesxe2x80x9d or xe2x80x9ccrossover type circuitsxe2x80x9d upon one or more selected surfaces and/or within certain component containing portions of the formed circuit board in order to allow multiple levels of circuits and/or electrical interconnections to be formed upon a single board surface or within a certain component containing portion of the circuit board, thereby desirably increasing the amount of electrical circuits which may be created upon and/or within the created circuit board (i.e., increasing the electrical circuit density).
These prior circuit board creating methodologies create and or form air-bridges and crossover circuits which do not typically and efficiently accommodate certain desirable circuit board interconnection processes and/or schemes such as and without limitation, the use of relatively heavy wire bonding (e.g., using aluminum wire having a diameter of about five thousandths of an inch to about twenty thousandths of an inch) or the direct connection of components to a surface of the board.
There is therefore a need to provide a method for producing a multi-layer electrical circuit board which overcomes some or all of the previously delineated drawbacks of prior circuit boards and/or circuit board forming processes, which selectively allows for the efficient creation of interconnection portions which extend within at least some of the various layers of the formed electrical circuit board assembly, and which further allows for the efficient and selective formation of air-bridges or crossover members and/or circuits which desirably accommodate diverse types of circuit interconnection processes.
It is a first object of the present invention to provide a method for producing a multi-layer electrical circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electrical circuit board forming methodologies and techniques.
It is a second object of the invention to provide a method for producing a multi-layer electrical circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electrical circuit board forming methodologies and techniques, which allows the formed circuit board to receive various contained electronic components, which allows for the selective, efficient, and reliable formation of electrically conductive interconnection portions which selectively and cooperatively allow for communication and/or electric connection by and between at least some of these various electronic components, and which allows these crossover members and/or air-bridges to be selectively created and/or formed without drilling.
It is a third object of the invention to provide a method for producing a multi-layer electrical circuit board which overcomes some or all of the previously delineated drawbacks of prior multi-layer electrical circuit board forming methodologies and techniques and which allows for the selective and efficient formation of air bridges and/or crossover members which are adapted to accommodate a wide variety of components and component interconnection techniques and/or assemblies.
According to a first aspect of the present invention, a method for making a multi-layer electric circuit board is provided. The method includes the steps of providing a first electrically conductive member; creating at least one protuberance upon the first electrically conductive member; providing a second electrically conductive member; providing at least one pre-circuit assembly; and attaching the second electrically conductive member and the at least one pre-circuit assembly to the first electrically conductive member, thereby creating a multi-layer circuit assembly and causing the at least one protuberance to extend within the multi-layer circuit assembly.
According to a second aspect of the present invention, a circuit assembly is provided. The circuit assembly is made by the process of providing a first electrically conductive member; creating a plurality of protuberances upon the first electrically conductive member; attaching a plurality of second electrically conductive members to the first electrically conductive members, thereby forming a multi-layer circuit assembly; and creating at least one interconnection path within the multi-layer circuit assembly by use of the plurality of protuberances.
These and other objects, aspects, and advantages of the present invention will become apparent upon reading the following detailed description in combination with the accompanying drawings.